As a work machine, there has been known a hybrid construction machine in which an engine drives a generator motor and a hydraulic pump, whereby an electric motor for an upper rotary body where a cab and the like are provided is driven by electric power generated by the generator motor while a hydraulic actuator for an operating device and a hydraulic motor for a traveling device are driven by a pressure oil from the hydraulic pump.
In the hybrid construction machine, the generator motor and an inverter are electrically connected to each other via an electric-power-supplying cable. The generator motor and the inverter are connected to the electric-power-supplying cable via respective connectors. Such a hybrid construction machine has been known for an arrangement that a terminal box is provided to a housing of the generator motor in order to house the connector of the generator motor (see, for instance, Patent Literature 1).